Surface Tension And Its Effecting Factors
Surface tension is the measurement of the cohesive forces between the molecules on a liquid’s surface. It is the characteristics that enables a liquid’s surface to hold together and withstand the pressure exerted by external forces.
Unit Of Surface Tension:
The SI unit of Surface tension is newtons per metre (N/m).
Factors Affecting Surface Tension:
Following significant factor can affect the Surface tension of the solution
Pressure:
It has inverse relation with the surface tension values. As it rises,the value of surface tension declines.
Temperature:
Surface tension increases with a decrease in temperature and decrease with an increase in temperature.
Impurities:
The presence of impurities on liquids surface lowers the cohesive forces, which in turn lowers surface tension.
Surface area:
Surface area has inverse relation with the surface tension as it decrease , surface tension rises.
Surface type:
Surface type that comes into touch with a liquid can have an impact on surface tension. For instance
- When water comes into touch with a hydrophobic surface, which repels water, the surface tension is higher
- While when water comes into contact with a hydrophilic surface, which attracts water the surface tension is lower.
Nature of liquid:
The surface tension of a liquid is determined by its molecular structure, effected by the type of liquid. The solution with Strong intermolecular forces have higher surface tension value.
INTERFACIAL TENSION
The forces of attraction between two immiscible phases, such as two liquids, a liquid and a gas, or a liquid and a solid, are measured by interfacial tension. It is the amount of energy needed to form a given area of the two phase contact.
Units of interfacial tention:
The SI units of Interfacial tension newtons per metre (N/m).
FACTOR AFFECTING INTETRTFACIAL TENTION:
The significant factor which effect interfacial tension are listed below:
Temperature:
Inversely related ,as temperature rises, interfacial tension decreases, but as temperature falls, it rises.
Impurity presence:
The presence of impurities at the interface of the two phases lowers the cohesive forces and, as a result, lowers interfacial tension.
Time:
The adsorption or desorption of molecules at the contact can cause changes in interfacial tension over time.
Type of surfactant:
Adsorbing at the interface, surfactants are molecules that can reduce the interfacial tension between two phases. Interfacial tension can be considerably influenced by surfactant type and concentration.
Nature Of The Two Phases:
The molecular nature of the two phases and the potency of the intermolecular interactions between them determine the interfacial tension between them.
Shear rate:
The pace at which the two phases are sheared or mixed can affect the interfacial tension.
Pressure:
As pressure increases, interfacial tension falls.
DIFFERENCE BETWEEN SURFACE TENSION AND INTERFACIAL TENSION:
| SURFACE TENSION | INTERFACIAL TENSION |
| The cohesive forces between molecules on a liquid’s surface are referred to as surface tension. |
The cohesive forces between two phases that are indistinguishable, such as among two liquids, a fluid and a gas, or a liquid and a solid, are referred to as interfacial tension, |
| It is the amount of energy needed to form a given area of liquid surface. | It is the amount of energy needed to form a given area of the two phase contact |
| The resistance of a liquid’s surface to external forces that would tend to expand its surface area is known as surface tension | The resistance of the interface betwean the two phases to outside forces that would tend to expand its area is what is meant by interfacial tension. |
| One liquid phase’s attribute is surface tension. | A characteristic of the boundary between two phases is interfacial tension. |
SIMILARITY BETWEAN SURFACE TENSION AND INTERFACIAL TENSION:
Although they measure separate phenomena, surface tension and interfacial tension are both indicators of the cohesive forces between molecules in a liquid.
